The importance of bare marine sedimentary habitats for maintaining high polychaete diversity and the implications for the design of marine protected areas

1. Bare intertidal sedimentary habitats have received relatively little attention compared with their neighbouring vegetated habitats. An ecological comparison of benthic faunal assemblages inhabiting tropical intertidal seagrass beds and bare sediments has been made to assess the faunal similarity between the two habitats in south-east Asia. 2. The poorly developed taxonomy of most invertebrate taxa in the region precluded the full identification of many faunal groups. Only the polychactes - which accounted for 76% of all the macrofaunal organisms collected - were identified to the lowest possible taxonomic level, yielding 177 nominal species belonging to 35 families. Ecological analyses suggested that although each habitat had a distinct polychaete assemblage, there were few differences between habitats based on a range of calculated assemblage diversity metrics. 3. Further analyses were applied to the data to test the performance of three strategies for optimizing the selection of sites for inclusion in potential marine protected areas. Strategies were based either on the total number of species, the number of rare or endemic species, or on the level of species richness (used as a surrogate for community structure). 4. All three strategies consistently captured above average numbers of species at most levels of conservation intensity. The merits of each strategy are considered in turn. Copyright (C) 2009 John Wiley & Sons, Ltd.